Uptake of doubly-labelled phosphorylserine in rat brain and intestinal mucosa in vivo.
Doubly-labelled phosphoryl-L-serine with a [14C]/[32P] ratio of about 1, was given orally to female rats as a single dose (50 mumoles/100 g body weight), and the radioactivity levels of [14C] and [32P] labelling, together with their ratios, were determined in the small intestine and brain tissue of the rat after 10, 15, 30 and 60 min from administration. Phosphoryl-L-serine enters intestinal mucosa as an intact molecule for short times after dosing, and is then hydrolyzed to free serine and orthophosphate after 10-15 min from administration. The amount of serine found in 1 g of fresh weight of intestine after 30 min averaged to 8-9% of the given dose, and was higher than that detected at the same time after the administration of equimolar amounts of serine. Brain tissue did not show to contain labelled phosphorylserine, but again the levels of cerebral labelled serine were higher than those found after administering serine, averaging after 30 min to 0.2% of the given dose.
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002250:Carbon Radioisotopes; D002851:Chromatography, High Pressure Liquid; D005260:Female; D007413:Intestinal Mucosa / Q000378:metabolism*; D010761:Phosphorus Radioisotopes; D010768:Phosphoserine / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012694:Serine / Q000031:analogs & derivatives*
D002250:Carbon Radioisotopes; D010761:Phosphorus Radioisotopes; D010768:Phosphoserine; D012694:Serine